Integration of acrylate polymer in sol-gel silica depending on their - PowerPoint PPT Presentation

Integration of acrylate polymer in sol-gel silica depending on their molecular weight Anthony Maçon 1 1 Imperial College of London, UK Confidential :) Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 1 / 17

Outline Introduction 1 Aims and Objectives Polymer synthesis and characterisation 2 Polymer Characterisation 3 Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 2 / 17

introduction Acrylate polymer can have different chemical properties and architecture Monomer organisation Polymer Architecture Homopolymer Star Branched Statistical Copolymer Brush Block Copolymer Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 3 / 17

Aim & objectives Aim How cross linking acrylate polymers are integrated in the silica matrix depending on their molecular weight objectives Use the Regulated free radical polymerization Characterised the polymerisation reaction Characterise the hybrid Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 4 / 17

R 0 (x10 − 3 ) Tageted M w DP ni 30kDa 120 8.3 15kDa 60 16.6 7.5kDa 30 33.1 2.5KDa 10 99.4 C monomer =1mol.L − 1 C 0 = n initiator n monomer = 1 . 5 % n CTA n monomer = variable R 0 = T 0 = n trioxane n monomer = 5 % Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 5 / 17

Chain Transfer constant                                                                                        ( 1 [ M ] = d [ T ] [ T ] ) i = C T d [ M ] DP n Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 6 / 17

Chemical Structure : NMR NMR 0 15 13 C ppm 30 45 60 75 4 3.5 3 2.5 2 1.5 1 0.5 1 H ppm Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 7 / 17

Chemical Structure : NMR       2.5kDa Intensity (a.u.)   7.5kDa Atatic (mr) / Syndiotatic (rr) 15kDa Tageted M w tacticity (rr/mr) 30kDa 1.85/1 30kDa 15kDa 1.80/1 7.5kDa 1.70/1 4 3.5 3 2.5 2 1.5 1 0.5 2.5KDa 1.44/1 1 H NMR (ppm) An increase of the tacticity of the polymer is observed with the increase of the molecular weight. Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 8 / 17

Chemical Structure : FTIR 1070 Si − OCH 3 791 CH 3 rocking 30kDa 15kDa 1140 C − O + skeletal C − C 7.5kDa Absorbance (a.u.) Absorbance (a.u.) 2.5kDa 2.5kDa 1270 C − O strech out of phase 1190 Si − OCH 3 1239 strech C − O in phase 1725 C=O 981 CH 3 rocking 1466 C − H 2 scissor bend 845 Si − C 7.5kDa 1400 C − H 3 sym bend 15kDa 30kDa 1650 1450 1250 1050 850 650 3000 2500 2000 1500 1000 Wavenumber (cm − 1 ) Wavenumber (cm − 1 ) Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 9 / 17

Size of the polymer : GPC & Dynamic Light Scattering                       Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 10 / 17

Synthesis method : Inorganic weight percent The mass of the polymer m Poly is known. The mass of TEOS, m TEOS , used, is calculated to get a final Inorganic weight percent of I w .                                                                  Inorganic Weight % Iw mSiO 2 + mSiO 1 . 5 1 − Iw . nPolymer . Mw . Organic − nPolymer . Mw . SiO 1 . 5 I w = mSiO 2 + mSiO 1 . 5 + mOrganic ⇒ n TEOS = Mw . SiO 2 1 mol of TEOS gives 1 mol of SiO 2 and 1 mol of polymer gives 1 mol of SiO 1 . 5 Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 11 / 17

Synthesis method : Ratio The classical definition of the R ratio can’t be used in the study. Network precursors are also introduced by the polymer which counts only 3 alkoxy groups where TEOS has 4. Therefore, H 2 O and the catalyst are introduced relatively to the number of mole of alkoxy group. Ratio definition n Alkoxy = 3 . n Polymer + 4 . n TEOS nH 2 O nCatalyst nEtOH R H 2 O = nAlkoxy ; R Catalyst = ; R EtOH = nAlkoxy nAlkoxy Table : Reagent which is needed for 1g of polymer and R H 2 O =1, R Catalyst =0.01, R EtOH =1 M w (g.mol − 1 ) D (g.mL − 1 ) Reagent n (mmol) V (mL) Ethanol 46.07 0.789 32.2 1.88 H 2 O 18.01 1 14.3 0.258 HCL 1M 1 0.32 0.322 TEOS 208.33 0.933 5 1.123 Alkoxy group - - 32.2 - Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 12 / 17

Chemical Structure : FTIR 30kDa 30kDa 15kDa 15kDa 7.5kDa Absorbance (a.u.) 7.5kDa 2.5kDa 2.5kDa Absorbance (a.u.) 1650 1450 1250 1050 850 650 1650 1450 1250 1050 850 650 Wavenumber (cm − 1 ) − 1 ) Wavenumber (cm Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 13 / 17

Thermoanalysis 100 12 2.5kDa 90 7.5kDa DSC (mW.mg − 1 ) −− > exo 15kDa 80 10 70 Mass loss (%) 8 60 50 6 40 4 30 20 2.5kDa 2 7.5kDa 10 15kDa 0 0 125 250 375 500 625 750 125 250 375 500 625 750 Temperature ( o C) Temperature ( o C) Composition TGA DSC Residual mass inflection pt ( o C) exothermic peaks( o C) (%) 2.5kDa 366.8 377.2 &394.5 28.9 I29 7.5kDa 368.8 313.8 & 365 31.6 15kDa 363.2 302.7 & 368.2 29.5 2.5kDa 349.3 359 & 377.5 48.5 I50 7.5kDa 336.4 310.9 & 336.4 50.7 15kDa 302.1 296.2 & 315.1 52.5 Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 14 / 17

Thermoanalysis 70 60 50 [Si] ( µ g.ml − 1 ) 40 30 20 10 0 0 50 100 150 Time (min) Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 15 / 17

Mechanical properties Nonoindentation using berckvich indenter. 5 60 50% inorganic 50% inorganic, 2.5kDa Reduced young modulus (GPa) 50% inorganic, 15kDa 50 4.5 40 Force (mN) 30 4 20 3.5 10 0 3 0 500 1000 1500 2000 2500 2.5KDa 15KDa Displacement (nm) Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 16 / 17

The end Thanks for your attention Anthony Maçon (PhD) Integration of synthetic polymer in sol gel silica matrix Sol gel meeting 17 / 17

Silica – polysaccharide hybrids for bone tissue regeneration Intra-European Fellowship for career development (IEF) - Marie Curie Yuliya Vueva Sol-gel meeting 18 th April 2013 1

IEF Marie Curie – HABER Objectives The aim of the project is to create new bioactive porous hybrid scaffolds that fulfil all the criteria of a scaffold for bone regeneration Preparation and characterization of hybrids by incorporating in the sol-gel process natural polysaccharide polymers (Carrageenans, Alginates, Celluloses) naturally occurring, biodegradable, nontoxic used in the food industry and in medic, in the field of drug delivery provide an alternative and novel method for introducing calcium into the hybrids The principle challenge will be to produce hybrid materials with covalent bond between the organic (polysaccharide) and inorganic (silica) part of the hybrid with controllable degradation and mechanical properties matching the host bone 2